Numerous introducer sheaths and catheter systems have been developed for the endovascular delivery of a variety of medical devices, such as stents or angioplasty balloons. Typically, a guide wire is introduced into a vessel and advanced through the vasculature to a treatment site. A catheter is then advanced over the guide wire so that the distal end of the catheter is located at the treatment site. The catheter then may be used to transport and place any of a variety of medical devices or tools, such as stents, grafts, angioplasty balloons, atherectomy devices, etc., at the treatment site. The success of many minimally invasive medical procedures relies on the ability to precisely position such a catheter or sheath within a diseased vessel.
Endovascular procedures, such as angioplasty, may be complicated if the treatment site is near a bifurcation in a vessel. Complications may arise if, for example, one branch of the vessel will become closed or narrowed when an angioplasty balloon is inflated in the other branch.
It may also be necessary to treat both branches of a bifurcated vessel. For instance, when inserting a stent or graft in a bifurcated vessel to strengthen a diseased region of the vessel that spans both branches of the vessel, multiple stents may be required. Although such a procedure may be performed using previously known endovascular delivery apparatus and methods, the procedure may be difficult and time consuming, as it may be necessary to separately reinsert the catheter to place each of the stents.
Several prior catheter systems have attempted to address these difficulties. U.S. Pat. No. 5,720,735 to Dorros, for example, shows a catheter having a distal end with two branches. Two guide wires are used to deploy the branches of the distal end of the catheter into the two branches of a bifurcated vessel. A similar bifurcated catheter is shown in U.S. Pat. No. 5,613,980 to Chauhan.
A disadvantage of such previously known bifurcated access systems is that both branches of such systems are advanced through the vasculature simultaneously. Consequently, the delivery profile of such previously known devices may be quite large, herein the width of the distal end of the catheter is at least as wide as the combined diameters of the branching portions of the catheter. Consequently, access to narrow vessels is expected to be limited.
Additionally, if the region being treated with the previously known systems described in the aforementioned patents includes multiple branches, it may be necessary to repeatedly reinsert and reposition such catheter systems to treat all of the branches of the vasculature.
In view of the above, it would be desirable to provide apparatus and methods that permit rapid delivery and positioning of a medical device at a bifurcation in a vessel with an access device having a reduced delivery profile compared to previously known systems.
It would also be desirable to provide apparatus and methods that permit rapid delivery or positioning of a medical device within multiple branches of a vessel.